Gear grinder



June 8 1926'1 H. D. TANNER GEAR GRINDER Filed Nov. 24, 1923 INI/Enron A TTBRNEY Patented June 8, 1926.

UNITED STATES PATENT oI-ElcE HUBERT D. TANNER, OF HARTFORD, CONNECTICUT, `ASSIGrN'OlR. TO PRATT & 'WHITNEY COIPANY, 0F NEW YORK, N. Y., A. CORPORATION OI' NEW Gm GBINIDEB.

Application led November 24, 1923. Serial No. 876,748.

Tanner and Knowles, No. 621,30 led Feb-l ruary 26, 1923. l

In the above mentioned application, the gear being ground is rotated at a constant speed by means of a vertically arranged shaft directly attached to the lower end of the work carrying spindle. This rotation serves not only to rotate the gear blank about its own axis but also to actuate it bodily about in a closed or orbital path.

As the blank successively passes opposite straight sides of its orbital path, the abrasive wheel or wheels engage the teeth on 'the blank and grind them'to correct form.

The mechanism used in that application is such that 'a material portion of the time is taken up in moving the blank from one side to the other of the closed path, this period of the cycle taking place when there is no grinding action. I t is essential in grinding gears that the speed of the rolling lmotion of the blank be limited as the blank passes the wheels and is incontact therewith, but, during the remainder of the cycle,

" the speed of the gear may be greatly increased. It is therefore an object of the invention to provide a construction permitting the gear blank to be rolled past the abrasive Wheel at a slow speed and then rolled at a greatly increased 4speed when the gear is out of contact with the wheels. This has the effect therefore of increasing the ratio of grinding time to the total time 'consumed in' moving the gear blank about in its closed path and therefore increases the eticiency of the machine by reducing the amount of idle time.

I accomplish the above object by driving the work blank and work spindle from a shaft, the axis of which is fixed'and provide a gear train from this pivotal connection to the work spindle. This train of gears, by means of eccentric or elliptic gears, causes the work spindle to rotate at variable speeds while the driving shaft rotates uniformly. I position the work'spindle relative to its path so that the rolling action of the work blank is relatively slow exactly at the point or points where it passes the abrasive wheels and'is materially faster during the remainder or idle portions of its movement. As this variable movement must bey properly timed for each work `blank and orbital path about which it is actuated, I introduce change gears in the train of driving gears so that the mechanism maybe adapted for gears having widely different numbers of teeth.

Another object of the invention is to improve the driving means for the work s indle by mounting the driving shaft in a xed position shaft and connecting this-shaft to the work spindle by spur gearing. By these means, flexible couplings permitting the shaft to be oscillated in accordance with movements of the spindle are entirely avoided. i

This latter object is accomplished by placing the spindle driving shaft so that its axis coincides with the axis of the connection between the frame or base and one ofthe swinging arms forming the support for the spindle.

With the above and other objects in view, my invention consists in the features of construction and operation set forth in the following specification and illustrated in the accompanying drawing.

' In the accompanying drawin I have shown my invention in a specia form of spur gear grinding machine but it will be understood that the invention can be otherwise embodied and that the drawing is not to be constructed as definin or limiting the scope of the invention, t e claims appended to this specification being relied upon for that purpose.

In the drawing;

Figure 1 is a (plan view of portions of a gear tooth grin ing machine showing the improved mechanism connected therewith.

Fig.2 is a' side elevation partly in section showing the driving and guiding means for the Work spindle.

Fig. 3 is a plan view in section of the gear train for rotating the work spindle.

In the above mentioned drawing, I have shown but one embodiment of the invention which is now deemed preferable, but it is to be understood that changes and modifications may be made Within the scope of the ap-l pended claims without departing from the spirit of the invention.

Bjrieiy, my invention comprises in addi tion to the base, column, Wheel heads anc supports for the work spindle shown and described in the above mentioned copending application, the following principal parts: first, a driving shaft rotatably mounted about a vertical fixed axis, this axis coinciding with the pivotal connection between the column and one of the supporting arms for the'spindle; second, driving gears connecting th'e driving shaft with the work spindle, these shafts being mounted upon and moving with the swinging arms; third, a pair of eccentric or elliptical gears interposed `in these driving connections.

Referring more in detail to the iigures of the drawing, I provide a base 10 having a column 11 suitably supported thereon, which, at its forward portion, serves to support a swinging arm or frame 12. At the outer end of this frame or arm 12 is another cori responding arm or frame 13, the latter carry- A stantially as shown in Fig. 1.

ing thework rotating and supporting spindle 14 and the work arbor 15. As these supporting means are, or may be, subst-am tially similar to those definedin the above mentioned application, further description of them is unnecessary. l

Onthe upper horizontal surface of the base 10 are wheel heads 1 6 each preferably mounted on suitableadjustable slides 17 and 18 and in a manner permitting angular adjustment. thereof similar in every way to the heads disclosed in the above mentioned application. Preferably, two of these wheel heads are provided oppositely disposed sub l These wheel heads rotatably support abrasive wheels 19 adapted to engage the work upon radially extending surfaces.

On a forward horizontal surface of the base 10 is mounted a plate 2O having a generally oval opening 21 therein and, above this plate 20, is another plate or member 22 provided with an opening, the periphery of which is provided with teeth 23. These teeth 23'extend throughout its entire surface. Below the first mentioned plate 2O is an oscillating lever 24 which may beheld resiliently in opposite oscillated positions by means of a spring detent 25 ybearii'ig upon opposite sides of a stud 26 provided on the lever.

The Work spindle 14, which is rotatably mounted at the outer end-of the second freely swinging arm 13, is provided near its lower portion with a master gear 28 adapted to engage in the teeth 23 of the plate 22. Adjacent this master gear 28 is a roller or ball bearing 29 adapted to engage the wall of the opening 21 in surfaced plate 20. An-

other bearing member 30 is adapted to engage the walls of any elongated opening provided in the oscillating lever 24. It will be seen from the above description that the work spindle 14 may have a limited bodily movement in a closed orbital path, this path being limited respectively by the master gear 28 and its engagement with the toothed outline 23 and the ball bearing 29 in engagement with the plane surfaced outline 2l. Also, action of the oscillating lever 24 is such that the spindle 14 is held resiliently toward opposite oscillated positions against the pressure of the wheels 1'9 when in engagement with the work.

in order to rotate the work spindle 14, driving connections are provided extending from the vertical driving shaft 30 to a gear 31 on the work spindle 14, all of the intermediate gears being mounted upon one or the other of the swinging' arms or frames 12 and 13. As shown in Figs. 2 and 3, these gears are rotatably mounted on studs mounted directlyin the swinging arms 12 and 13, one of the studs or pivots for these gears corresponding to the axis of the hinged joint between the two swinging arms.

Between the first gear 32 of the train, which meshes with a gear 33 on shaft 30, and the next intermediate gear 34 is a pair of eccentric gears 35, the ratio between the members of this pair being one to one. llt will be seen therefore that the uniform angular motion of the shaft 30 and the rst of connecting gears 32 is transmitted into an irregular rotative movement of the intermediate gear 34. This irregular motion of the second eccentric gear 35 is transmitted from gear 34 through suitable intermediate change gear 36 to the gear 31 on the work spindle. Preferably the gears 31, 35 and 36 may be readily removed so that others of different sizes may be substituted. As the periods of the irregular motion obtained from the eccentric gears 35 must coincide with the movement of the master gear 28 about its orbital path, it is necessary to introduce change gears so that gears having different numbers of teeth which required orbits of varying lengths may be ground. For that reason lr. maire the last mentioned gears readily removable and adjustable so that others may be substituted.

By means of this train of connecting gears 33 to 31 and with the eccentric gears 35 interposed therein, the work spindle 14 and the gear blank thereon wiil be given an ir- @L regular rotative movementand, by reason of the engagement of the master gear 28 with its internal toothed path 23, the ,bodi ly or orbital movement of 'the work spindle 14 will also be irreguiar. rapid movement and another eriod of slow movement will take place during each complete rotation of the eccentric gears 35. lf therefore interpose the proper ratio between gears 31 and 34 in order to have these ec- `@ne period of E lll 1,5ee,oee Y centric gears rotate twice during each coinplete cycle of -movements of the work spin dle 14 about its orbital path. also position these eccentric gears in such manner- 'eccentric gears 35 ineke' two complete revolutions while the master gear 28 and the spindle 14 complete one movement about the.

orbit represented by the toothed opening 23 in member 22, the ratio between the gear 34 and the gear 31 on the spindle 14 corresponds exactly with the ratiobetween the number of teeth in the master gear and one half of the toothed outline 23.

By this above described construction, I allow the gear blank to engage the abrasive wheels 19 slightlylonger than would be possible with uniform motion applied to the work spindle 14, that is, with the eccentric gears 35 interposed, a larger proportion of the time the work blank is rotated may be given to the grinding operation than if the s eed were entirel uniform. The remaining motion o t e work spindle 14 which serves to position the gear blank in proper relation relative to the wheels 19 by virtue ot the eccentric gears takes place at the highest desirable or convenient speed.

What l claim is:

1. A gear tooth grinding machine comprising in combination, a base, an abrasive wheel mounted thereon, a work spindle supported. for movement in any direction while its axis is maintained in parallel positions,

a ear blank thereon, means to move said spindle about in an orbital path and to simultaneously rotate it about its center, said means imparting an irregular speed of orbital and rotary movement to said work spindle.

2. A gear tooth grindin machine coinprising in combination, a ase, oppositely disposed abrasive wheels mounted thereon, a

work spindle supported for movement in any direction while its axis -is maintained in parallel positions, a gear blank thereon, means to move said spindle about in an orbital path and to simultaneously rotate it about its center, said means'iinparting an irregular orbital and rotary movement (o said work spindle whereby said gear blank passes said wheels at a different speed than its speed in other parts of its orbit.

3, A gear tooth grinding machine comprising in combination, a base, an abrasive wheel mounted thereon, a work spindle supported for movement in any direction while its axis is maintained in parallel positions;

a gear blank thereon, a master gear on said spindle, an internal toothed member engaging said gear whereby movement of said-` work spindle is restricted to a closed path,

and means to rotate said spindle at an irre# gular speed.

4. A gear tooth rinding machine com-v prising in combination, a base, an abrasive` wheel mounted thereon, a work spindle supported for movement iii any direction While its axis is maintained in parallel positions, ai gear blank thereon, a master gear on said spindle, an internal toothed member engag" ing said gear whereby movement of said work spindle is restricted to a closed path, and means to rotate said spindle at an irregular speedwherebythe-spindle is revolvedv irregularly about its orbit and the gear blank passes the wheel substantially at its lowest" speed.

5. A gear tooth grinding machine comi prising in combination, a base, an .abrasive wheel mounted thereon, a work spindle supported for movement in any direction while its axis is maintained in parallel positions, a gear blank `mounted thereon, means to move said spindle about in an orbital path and to simultaneously rotate it about its center, and geared driving means for said spindle, one pair of said gears being mounted eccentrically of its periphery'whereby the motion imparted to the work spindle is ii'-` regular.

6. A gear tooth grinding machine comprising in combination, a base, a pair of oppositely disposed abrasive wheels mountedV thereon, a work spindle supported for movement in any direction while its axis 1s maintained in parallel positions, a gear blank mounted thereon, means to guide said spindle in a closed path while the gear blank is rotated to move the blank into and out of contact with the wheels, said means causing the blank to be moved slowly while engaged by said wheels and moved more ra idly when out of Contact with the wheels.

A ear tooth grinding machine comprising in combination, a base, oppositely disposed abrasive wheels mounted thereon, a work spindle supported for movement in any direction while its axis is maintained in parallel positions, a gear blank mounted thereon, means to move said spindle about in an orbital path-and to simultaneoiisl y rotate about its center, and geared driving means for said spindle, one pair of said gears being mounted eccentrically whereby the motion imparted to the work spindle is irregular, said gears being such that two periods et rapid motion and two periods of slow motion are induced during each revolution of the spindle about its orbit.

inl

8. A gear tooth grinding machine comprising 1n combination, a base having a co1- umn, an abrasive wheelmounted on said base, a pair of freely swingin arms mounted on said column, a .work spin le'supported at the outer end of said arms, means to guide said spindle in an orbital path while said spindle is rotating, driving means for said spindle comprising a shaft the axis of which coincides with the connection between the column and arms, and driving means connecting said shaft with said spindle.

9. A gear tooth grinding machine comprising .in combination, a base having a column, an abrasive wheel mounted on said base, a pair of freely swinging arms mounted on said column, a work spindle supported at the outer end of said arms, means to guide said spindle in an orbital path while said spindle is rotating, driving means for said spindle comprising a shaft the axis of which coincides with the connection between the -c'olumn and arms, and,driving means con- "..necting said shaft with said spindle, said column, an abrasive wheel mounted on 'sa-id Y spindle comprising a shaft the axis of which coincides with the connection between the column' and arms, and gears connecting said s shaft with said spindle. l

11. A gear tooth rinding machine comprising in combination, a base. having a column, an abrasive wheel mounted thereon,

a pair of freely Swingin arms mounted on said column, a work spin e supported at the outer end of said arms, means to guide said spindle in an orbital path while said spindle is rotating, driving means for said spindle comprising a shaft the axis of which coincides with the connection between the columnv and arms, and gears including change gears connecting said shaft with said spindle, said gears being` formed to rotate the spindle at dierent and irregular speeds.

In testimony whereof, I hereto aiiix my signature.

HUBERT D. TANNER. 

